The technique for artificial insemination of animals by means of vaginally introducing a dose of semen into a female in heat is widely used today. A catheter and sometimes, depending on the specific insemination point, a cannula fixed thereto must be used to reach the vagina of the animal.
The catheter usually has a handle at the end which remains outside the animal facilitating handling as well as the connection of said catheter to the container bag for containing semen. This bag usually has a cannula in the semen outlet hole to favor said connection between the catheter and the container bag.
A large variety of container bags for containing semen for artificial insemination of animals can be found in the state of the art. Some of them have one and the same semen inlet and outlet hole. These cases have the drawback that the hole through which the semen is first introduced undergoes certain deformations due to the introduction of the filling nozzle therein, such that the connection of the catheter in said semen outlet hole then becomes defective, a proper securing thereof not being achieved.
Container bags for containing semen with a semen inlet hole and another semen outlet hole solving this problem are also found in the state of the art. This case has the drawback that after insemination, some stagnant semen remains in the conduit of the cannula existing in the outlet hole for the connection of the catheter therein, where the spermatozoids eventually die. These dead spermatozoids form a barrier in subsequent inseminations, reducing process effectiveness.
Reference documents US2003163110, FR2820029 and ES2247888-A1 can be mentioned as examples of the state of the art.
The first reference document US2003163110 relates to a bag for packaging semen formed by two plastic walls joined in such a manner as to delimit a pouch for receiving the semen. It has an evacuation conduit the end part of which is closed by said joined walls when the bag is closed. Said conduit comprises a cannula having two open ends force-fitted therein, its first end being suitable for communicating with said pouch, whereas its second end located close to the end part of the conduit has a frustoconical- or almost frustoconical-shaped constriction. Said conduit further communicates, over a fraction of its length, with at least one area located not far from the end part in which the two walls are not joined.
In the second reference document FR2820029, the container bag for containing semen is formed by two plastic walls joined so as to define a pouch for receiving said substance. Said pouch has communicated therewith an evacuation conduit the end part of which has a cannula with two open ends when the bag has not been opened. This cannula is inserted into conduit, such that its first end is capable of communicating with said pouch, whereas the second end is located close to the end part of the conduit.
The cannula in turn comprises at its second end a blind end finish which is physically separated or separable when the bag is closed. The joined walls surround the cannula and its blind end in a leak-tight manner, so when a force is applied on the blind end in a direction perpendicular to the plane of the bag, one of the plastic walls tears at the level of the second end of the cannula, said cannula being directly accessible.
The applicant is the proprietor of the mentioned third reference document ES2247888-A1. In this case, it relates to a device for artificial insemination of animals having a bag made up of at least two sheets of thermoplastic material sealed through a perimetral structure, such that a receptacle containing the semen is defined communicating with the outside through an inlet hole and an outlet hole.
A cannula having a certain thickness is tightly fitted in the outlet hole, part of the cannula being outside the bag and the cannula having a plug for closing the outer part thereof. Said plug comprises a stem integral with the head of the plug, such that when the plug is placed in the outer part of the cannula, the stem is tightly fitted at least along the entire length of the cannula.
In the case of the first two mentioned documents of the state of the art, it can be observed how the cannula existing in the outlet hole of the container bag has no plug, whereby the main drawback is that performing more than one dose of insemination is difficult.
Specifically, the cannula in the first reference document US2003163110 has no plug at all, rather its second end is close to the end part of the outlet conduit and the section thereof has a constriction at said frustoconical-shaped end. This makes the application of successive doses with the same bag difficult and in the event of doing so, there would be a high risk of unwanted semen spillage as well as the entry of hazardous elements or contaminants into the bag.
The cannula in the second reference document FR2820029 also has no closure plug, but rather a blind end finish which seals the bag when the bag is closed and which must be removed or broken to be able to open the cannula. This facilitates tearing open the bag, but it also has the drawback of complicating the application of new doses of semen with such bag without the risk of unwanted spillage and of possible contaminations due to the entry of hazardous elements into the bag.
If the blind end finish is not broken but rather removed, said end finish could be returned to that position for closing the cannula, but in that case the drawback is that semen accumulates inside the conduit of the cannula which remains leak-tight, whereby the spermatozoids die and are a barrier in subsequent inseminations for the advancing spermatozoids remaining in the bag, significantly reducing process effectiveness.
It is observed in the third reference document ES2247888-A1 that a solution to these problems is provided by means of a closure plug closing the outer part of the cannula, having a stem tightly fitted therein along the entire length of the cannula. This enables applying several doses of insemination without spillage or possible contamination problems, while at the same time preventing stagnant semen from remaining inside the cannula since the plug is located therein.
Nevertheless, this solution continues to pose certain drawbacks such as the fact that when opening the bag, the closure plug for closing the cannula falls to the ground where the liquid manure of the animals is located, whereby said plug is not reusable since it would contaminate the bag with hazardous agents.
Although this can be solved by using a new plug, in addition to the continuous need for providing new plugs, there is a problem where the disposed plugs are collected together with the liquid manure subsequently used as soil fertilizer. The problem is that the plugs are also disposed of along with the liquid manure and the soil is ultimately contaminated.
Another drawback present in all the solutions of the state of the art is that the current manufacture of such container bags uses two sheets of plastic material welded to one another, in which the outlet cannula has been previously introduced between them. The outlet cannula is thicker than the sheet of plastic material and it must be made in a plastic material that does not deform under welding heat, so the cannula is secured to the sheets more by pressure than by heat fusion. This means that the weld with the bag is not a high quality weld, such that most of the times the outlet cannula sinks into the bag in response to the pressure exerted on said outlet cannula when the insemination catheter is placed therein.